关键词: 流量, 潮位, 河口水质, 氯度, 盐水入侵距离

Abstract: Water pollution by salt water intrusion is primary influence factor of water quality in the Changjiang Estuary, and its intensity is mainly controlled by river discharge and tidal level in the estuary. The construction of the projects of water transfer from south to north and the Changjiang Gorges Reservoir will change the discharge of the Changjiang River, meanwhile, global climatic warming will cause relative sea-level rise of 0.5-1.0m in this region in the middle of next century. By correlative analysis of discharge, tidal level and chlorinity. the distance of salt water intrusion etc., the changes of water quality in the South Branch of the Changjiang Estuary in future have been estimated by the changes of discharge and tidal level. As a result, serious harm will appear in dry season of dry year of discharge less than 13×10³m³/s at Datong station. The construction of the Changjiang Gorges Reservoir will improve water quality of the Changjiang Estuary to some extent from Jan. to Mar., but it will aggravate water pollution of the estuary in October of dry year. When discharge more than 15×10³m³/s at Datong station, the effects of the changes of discharge and tidal level in future on water quality of the estuary is very small.

Key words: discharge, tidal level, water quality of the estuary, chlorinity, the distance of salt water intrusion